Periodically I get an error sounding tone playing, but I can't see any reason, just now it was going constantly, the only thing that stopped it, other than switching phone off, was activating airplane mode, however, I tried every connection in turn to see what wireless connection it was that was causing it, and none of them made any difference, I tried bluetooth, wifi, wireless screen, mobile network, gps, but they didn't stop the noise. I just left airplane mode on for 5 minutes, and when I switched it off the phone made the noise a couple of times, but now seems to have stopped. I also used task manager to kill all tasks, in case it was a programme or app running in the background that was causing it, but no joy. It did it quite a lot when I first had it new, but then stopped, but seems to have started again now, it's been doing it a lot to day specifically. Anyone any ideas? The tone it plays is not a preloaded ringtone or notification tone that I can find, it is a 3 note descending tone, that is off key, and sounds discordant.
Can anyone help me work out what it is?